Heating system



Aug. 16, 1927.

R. R. EMERSON HEATING SYSTEM Filed Dec. 5, 1925 Patented Aug. 16, 1927.

. UNITED] STATES PATENT- QFFICE. v

RALPH RAY mmnsomor BROOKLYN, NEW mix, ASSIGNOB 'ro. HOFFMAN SPECIALTY comrnnr, or WATEBBUBY, CONNECTICUT, 'A conroaa'rxon or ILLINOIS.

H ATING mum,

"Application niedmember a 1925. Serial jab. 72,964.

Tlhepresent inventionrelates to low pressure heating systems equipped with automatic means for causing or permitting steam to pass'from the pressure s'ideof the system to the return line, directly and Without first passing through the radiators, whenever the boiler pressure rises above a. predetermined degree. By the term"pressure side of the system, or equivalentterms, as used in this specification, I-mean the boiler 01' any part of the steam supplymainforconnection between the boiler and the supply main. The means for permitting'direct passage of steam from the supply line to the return line, referred to above, include such devices as the differential 7 loops disclosed in the Letters Patent of the United States to George 1). Hoffman, No."1,57"2,482, granted February 9, 1926, and entitled Vapor heating system with differential loop, and the application for such'Letters Patent filed byWiHiam K. Simpson, September 30, .1925, Serial No. 59587, entitled"Difierentia.l loop for heating systems, as well as other means or apparatusadapted to serve essentially the same purpose as such loops. In this specification I will call such means by theterm steam crossover device. intending by tha-t'term toinc-lude any apparatus which will operate to admit steam into theretur'n line and so prevent water being forced out of'the boiler into the return line when the boiler pressure becomes abnormally high, as explainedin said applications. I

The present invention does not involve any new principles or construction in such a steam crossover device, but'is concerned only with a newmode of combination .or application of-such. a device withv and in a low pressure steam heating system; and the new step of the invention consists mainly in roviding the system "with a dry return inc, and in connecting the loop, or equivalent ,crossover device withthe-dryreturn line at or near the highest point thereof. This point ofcon'nection, and its location, may be designated generically as the high point of the return line, meaning b thatterm not necessarily the absolutely highest point, butone sufficiently near the absolutely highest point for the purposes of this invention and the-results to be obtained as h'ereinbefore explained; Preferably the dry return line is arranged with its highest point as near as practicable to the boiler, and running thence on a downward pitch to a con nection with a" wet return line which enters" the lower part of the boiler; and said dry return line makes a circuit. of the building in such, fashion that it'may be connected withthe return outlets of the various'radiators'or heatingcoils. The term dry return line does not mean that the-line so called contains no water, but signifies that it is so high above the normal water level of the boiler, and so large, that the -water of condensation entering it from the radiators will run off without filling it, except possibly for very brief periods. y

.In further explanation ofthe invention attention is directed to the drawings'furnished herewith, in which; Y 7

Figure l-is a perspective view of a steam heating system of the sort to which my inventionis applicable," andhaving therein a dry return line and a differential loop connected to the high point of the return line 5 Figure 2 is'a fragmentary view of the high est part of the return line and the loop or crossover device connected therewith, illustrating graphically the actionwhich takes place as a result of so connecting the loop with the return line. Like reference characters designate the same parts in'both figures The above mentioned Figure 1 represents a typical installationcontaining the present invention, in which a is a steam boiler, 7b is the steam line orsupply main connected with the boiler by communicating pipes c, d and c, d; the two latter comprising what is commonly termed a boiler header. 6+6 are radiators or heating coils and fis the dry return line. Such return line makes a the boiler' to their ends at the termination of the circuit of the building, and at their latter ends are connected by descending legs 19- and f, respectively, with the wet return line f which is-connected'with the boiler in a suitable fashion for permitting Water of condensation to return thereto.

' The letter is representsa steam crossover device of the type known commercially as the Hoffman differential loop, the pre-v it is constructed with two legs containing water columns connected together at their fill directly from the steam side of the system to.

the return line when such water column is I sufficiently depressed by steam pressure. By

virtue ofthesecharacteristics, whenever the steam pressure in the boiler rises to suclra degree as would otherwise cause the water to back up into the return line in volume sufficient to uncover surfaces in the boiler which are exposed tointense heat and should always be covered with water, then steam is admitted to the return line up to a sufficient pressure to oppose and prevent such backing up of the boiler water. All this, is fully explained in the prior patent aforesaid and is repeated here simply to make clear the pur-. pose and utility of such. loop, or equivalent devicefor allowing steam on occasion to pass directly from the steam side of the system to the return line. The same function and effect may be performed by specifically different means than the Hoffman differential loop; wherefore, since my invention is not concerned with the details of such loop or any improvement therein, neither is it restricted to said loop or any other specific crossover device; There is connected with the crossover device, or with the return line near such device, an automatic thermostatic valve 722 which is normally open to'the atmosphere when the boiler pressure is no higher than that prescribed as the normal pressure for causing circulation of steam, but is closed by thermostatic action when live steam reaches it after passing the loop, in order to prevent loss of steam.

In accordance with my invention I connect the loop or equivalent steam crossover device with the return line at the highest part of the latter; in other words at the high point of the return line, according to the definition of the term high point previously given. This connection is shown at o in the drawing; and as there shown is made through an upright pipe 0 which runs from the high part of the line to a connection with the wet return line in order to lead directly back to the boiler any water which may overflow from the'loop. Preferablythis pointv OfICQDi necti'on is so near. theboiler". that thegsteam connection to the loop may be so short as to 7 reduce as much as possible the condensation from 'thelloop is above the air already in-the sspf steam flowing to the return line. It is to be understood that at such times the return line is full of air because the thermostatic valve is normally open, and also because ,air' passes into the return 'line from the radiators when steam is turned into the latter. Thuswhen steam passes into the return line through the loop, it can only penetrate the line until it has compressed the air already therein to an equal pressure. .As the line is laid with a downward pitch, and as steam is lighter than air, a definite demarkation plane is established at-some point in the return line, as

tit!

designated graphically at p-in Figure 2; all

'the space in the line lower than this plane being filled with air, and the space in the line above the plane being filled with steam. The particular location along the length of the line in which this plane is found depends on the steam pressure and the downward pitch of the return main and will be different at different times and under different conditions, But this is unimportant. [The important fact is thatwhen steam enters the return line it forces and, compresses the air ahead of it, but can only penetrate the line to the pointwhere it has compressed the air to equal pressure. Another important fact is that the flow of steam in entering the return line takes place in the samedirection as the flow of water of condensation passing from the radiators to the wet return line.

lVhen the crossover device is connected to a low part of thereturn line, steam admitted by such device is able to pass the air previously in the line and to flow in the opposite direction to the water flowing downward through the line, retarding and backing up the watervand causing noise or water hammer. As a result :of my new combination and arrangement there is no noise when steam flows into the returnline because it does notblow back the water of condensation and cause it toform slugs of water ob structing the pipe. The distance to which steam can enter the return lineis limited and there is less condensation of steam and therefore the condition of equilibrium which prevents .furtherinflux of steam is Kill) reached more quickly WVhen the automatic valve is opened and the heating systemfis being IQllGVGCl of air, the path of the out fiowlng air is upward toward the automatic relief valve,rwherefore the air escapes more easily, quickly and completely.

By the use of this invention an increased flexibility in laying out heating systems is made possible; because the high point in the dry return line can be carried above the high point in the steam main; always providing, of course,that the high point in the return line is lower than the traps on the radiators.

This arrangement is not essential, however,

and in some installations the crossover device is connected to the absolutely highest point in the dry return line, without a direct downward or drip connection to the wet return line.

This invention is applicable to all low pressure steam heating systems, including both the sc-called vapor and vapor vacuum systems. The only difierence between the 1 two systems thus identified is in the character of the valve m: that used with vapor systems being normally open except when steam passes the crossover device, and that used in the vapor vacuum systems being closed by an additional check valve which prevents entrance of air from the atmos phere when the steam pressure in the system is below the atmospheric pressure. But in all these systems the function and effect of the loop or other crossover device is the same. 7

The appended claims are to be construed in the light of the definitions hereinbefore given, and particularly with the understanding that the foregoing specific description of details of construction is illustrative or representative and not matter of limitation.

Thus in a situation where there I would normally be a very small waterline What I claim and desire to secure by Letters Patent is:

1. In a low pressure steam heating system a boiler, a steam line and a dry return line, a steam crossover device connected'to the steam side of said system and to the high point of the ret-urnline, and a drip 'connection from said device to the low part of the return line.

2. In a heating system a steam boiler, a steam line, a dry return line having a downward pitch and a return connection to the boiler from its lower end, and a steam crossover device coupled with the steam side of the system and having a; discharge outlet connected upwardly to the highest part of the dry return line, and downwardly to the" wet return line.

3. In a steam heatingsystem, a boiler, a steam line, a. dry return line arranged with a downward pitch, a wet return line leading from the lower end portion of said dry return line to the lower part of the boiler, a steam crossover device connected to receive steam from the steam side oft-he system and having" a steam outlet, and a thermostatic valve opening to the outer atmosphere. said outlet and said thermostatic valve bot-h being near the highest point of such line.

4. In a steam heating system, a dry return line and a steam crossover device'between said line and the pressure side ofthe system, said crossover device being connected with the dry return line at the high point of the latter.

'5. In a steam heating system. a boiler, a steam line, a dry return line extending in approximate parallelism with said steam lineand with a downward pitch,.heating in connection with the-dry return line units connectedto said steam and return lines, a steam crossover device connected to receive steam from the boiler, and a pipe in connection with the outlet side of said crossover device extending upwardly to connection with the high point of the dry return line and downwardly into connection with the lower part of the return line.

In testimony whereof I have afiixed my signature.

RALPH'RAY EMERSON, V 

